FS98O21 datasheet(21/136 Pages) FORTUNE

21 / 136 page

FS98O21

Rev. 1.7

21/136

Memory Organization

Program Memory Structure

FS98O21 has an 11bits Program Counter which is capable of addressing a 2k x 16bits program memory space

and a 6 level depth 11bits Stack Register. The Start up/Reset Vector is at 0000h. When FS98O21 is started or

its program is reset, the Program Counter will point to Reset Vector. The Interrupt Vector is at 0004h. No matter

what ISR is processed, the Program Counter will point to Interrupt Vector. Please see Figure 3-1.

P rogram C onter

S tack L evel 1

S tack L evel 2

S tack L evel 3

S tack L evel 4

R eset V ector

Interrupt V ector

0000h

0004h

07FF h

S tack L evel 5

S tack L evel 6

Figure 3-1 FS98O21 program memory structure

Data Memory Structure

FS98O21 has a 256 byte SRAM for Data Memory. The data memory is partitioned into three parts. The area

with address 00h~07h is reserved for system special registers, such as indirect address, indirect address

pointer, status register, working register, interrupt flag, interrupt control register. The address 08h~7Fh areas

are peripheral special registers, such as I/O ports, timer, ADC, signal conditional network control register, LCD

driver. The address 80h~0FFh areas are general data memory. Please see Table 3-1.

Table 3-1 FS98O21 Data memory structure

Start Address

End Address

Data Memory

00h

07h

System Special Registers

08h

7Fh

Peripheral Special Registers

080h

0FFh

General Data Memory

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